As for brand, all you need to know is three letters: CTS.
To go with those three letters, you need to know a few numbers and word combinations:
For Fender style volume: 250 kohm audio taper
For Fender style tone: 250 kohm linear taper
For large passive humbuckers, 500kohm audio taper
These are generalities. If you can get the schematic to your particular bass, then start with what the manufacturer recommends. Then you can experiment later if you don't like the "stock" characteristics.
There are variations on a theme, which some people really like. For example, for a volume pot I like to take a 500 kohm audio taper and bridge the wiper and output lug with a 1 meg resistor to get the effect of a hybrid taper 330 kohm volume pot, with a 500 kohm linear tone pot and .033 orange drop tone cap instead of the usual .047, to raise the hinge frequency a little bit. But that's just me.
The value of a tone pot is not that critical because it is directly grounded. The value of the volume pot can be critical, because with it being grounded on the off lug instead of directly, different value pots can load the pickup differently. Broadly speaking, the higher value the pot, the more pronounced the resonant peak of the pickup response, which if moderate can make it sound with more presence, and in the extreme spikey and harsh. Conversely, the lower the value of the volume pot, if moderate, can make the pickup sound more smooth, and in the extreme dump top end and make it sound dull.
Low-Z active pickups are a whole 'nutha kettle of fish, and do not correlate.
